This research proposal seeks to rigorously characterize the molecular biology of the acute measles virus infectious cycle, and of its progeny - the completed, infectious measles virion. Establishing the details of measles virus replication during acute, productive infection is prerequisite to the long-range goals of my laboratory's research program - those being the identification of the mechanism(s) by which persistent measles infections are established and maintained, and the assessment of the role played by such infection in the pathogenesis of chronic human disease. On the basis of our previous studies, we have selected the HeLa tissue culture suspension cell as the laboratory 'model' for the examination of the replicative strategy by which progeny virus are generated during acute, productive infection. Using methods and probes already developed, the synthesis and structure of the virus-specified macromolecules will be analyzed, and their role(s) in the reproduction of the infectious virion established. Particular attention will be given to as yet undefined features of measles virus and of its acute infectious cycle, including: (1) the pathways of viral structural protein synthesis, processing, assembly, and release as infectious progeny; (2) the transcription of viral mRNAs and the definition of the translation product each encodes; (3) genome replication; and (4) assessment of the possibility that non-structural information is encoded by the measles genome. Furthermore, the clarification of several of the above features of measles virus reproduction would be best addressed using highly simplified, well-defined, and easily manipulable in vitro systems. We, therefore, plan to pursue the development of in vitro transcription (and perhaps in vitro replication) system(s) with which to examine these virus-specified synthetic processes when removed from host-cell influences.